What suffices for opening the prayer

Ibrahim said: If a person, when beginning the prayer, says "Subhan Allah", "Allahu Akbar" or "La ilaha illallah", it is valid, and two prostrations of forgetfulness (sajdat al-sahw) are due.

Al-Hakam said: If, when beginning the prayer, one says "Subhan Allah" or "La ilaha illallah", these words will take the place of "Allahu Akbar".

Abu al-Aliyah was asked: "With what words did the prophets begin the prayer?" He said: "They began the prayer with words of tawhid (affirming Allah's oneness), tasbih (glorifying Allah) and tahlil (saying La ilaha illallah)."

Al-Sha'bi said: If you begin the prayer with any of the names of Allah Almighty, it is valid.